Speculum.



No. 682,832. Patented Sept. I7, 190i. J G. MDPHERSUN.

SPECULUM.

(Application filed Dec. 29, 1899.)

(No Model.)

Ila kn (0r.

"itnepgzw. @WLM Unirrn terns J GORDON MOPHERSON, OF TORONTO, CANADA.

SPECULUM.

SPECIFICATION forming part of Letters Patent No. 682,832, datedSeptember 17, 1901. Application filed December 29 1899. Serial No.741,989. (No model.)

To aZZ whom it may concern:

Be it known that I, J GORDON MOPHERSON, veterinary surgeon, of the cityof Toronto, in the county of York, in the Province of Ontario, Canada,have invented certain new and useful Improvements in Speculums, of whichthe following is a specification.

My invention relates to improvements in speculums adapted to hold openthe mouths of horses, cattle, and other animals; and the objects of theinvention are, first, to devise a construction for the ends of the sidepieces of the speculum whereby the incisor-plates may be held rigidly inposition under all circumstances, and, secondly, to provide a means forrelieving the strain of the pivotal pins of each set of side pieces; andit consists, essentially, first, of providing the ends of the sidepieces with an. overhanging lip, which extends over the ends of theincisor-plates, and, secondly, of a concentric socket formed in eachupper side piece and designed to receive a correspondingly-shaped end ofeach lower side piece, the pin of which extends through the upper sidepiece into and through the end of the lower side piece and is relievedfrom the strain by the construction aforesaid and as hereinafter moreparticularly explained.

Figure 1 is a perspective View of my speculum. Fig. 2 is a detail of theend of each side piece. Fig. 3 is a detail of the incisorplate. Fig. 4is a detail of the hinge.

In the drawings likeletters of reference indicate corresponding parts ineach figure.

A A are the upper side pieces, and B B the lower side pieces. The upperside pieces are provided with the end offsets a and the overhanging lipa. The lower side pieces B B are also provided with similar offsets band the forwardly-projecting lip 12.

O is the upper incisor-plate, which is provided with the usual notchedends 0 c, which are designed to fit between the lips a, and the offsetsa and D are the screw-pins, which extend through the notches c into theoffsets a when the incisor-plate O is fitted in position, as indicated.D represents corresponding pins, which extend into the offsets I)through the notches c in the lower incisor-plate C. It

will be noticed that the rear end upper pieces are provided with slotsA, the upper ends of which are formed with arc-shaped sockets A (seedetail Fig. 4,) within which fit the substantially circular ends B ofthe lower side pieces B.

E represents the pivot-pins, which extend through the upper side piecesand the substantially circular ends of the lower side pieces, asindicated. It will be readily seen that as the substantially circularends B are a snug fit into the socket A in each of the side pieces A thestrain is relieved from the pin E. It will also be noticed that as thesub= stantially circular ends are eccentrically pivoted within thesockets A they will form cam stops. Thus as the side pieces are spreadthese cam-shaped ends B will form a subsidiary stop to prevent theincisor-plates being spread too far apart. Of course the ordinary way ofdoing thisis by means of the notched adjusting-bars F, which aredesigned to engage with the lower end of the upper side piece A, insidethe slot A. Such adjusting bars are pivoted on the pins f in the lugs B,and are spring-held by the springs 12 The adjusting-bars F are of theusual construction and are designed to regulate the distance apart ofthe free ends of the hinged side pieces, and consequently of theincisorplates. I-Ieretofore the incisorplates frequently slipped out ofplace when the pressure of the incisor-teeth of the horse or otheranimal was exerted upon them, such plate slipping backwardly over theside pieces. The pins E, also, were, on account of the great strainexerted upon them, frequently broken or forced out of place. By myinvention, however, both of these defects are overcome and theveterinary surgeon operating upon the horse or other animal can do sowith impunity and without any fear of the parts becoming broken or outof place.

What I claim as my invention is- 1. In aspeculum,the combination withtheincisor-plates having the end notches, of the side pieces providedwith the offsets upon which the ends of the plate rest, the screw-pinsextending through the notches into the offsets and the overhanging lipsextending over the ends of the plate and designed to hold them of saidpieces coacting with Walls of said sockin place as and for the purposespecified. ets to provide a subsidiary stop, substantially 2. Thecombination with a speculum having as described. upper side pieces withdepending slotted ends J GORDON MC'PHERSON. 5 and sockets at the ends ofsaid slots of the Witnesses:

lower side {pieces having cam-shaped ends 8. BOYD, pivoted in saidslotted ends, the cam portions 1 W. AMEs.

